/* * Written by J.T. Conklin . * Public domain. * * Adapted for `long double' by Ulrich Drepper . */ #include RCSID("$NetBSD: $") /* e^x = 2^(x * log2l(e)) */ ENTRY(__ieee754_expl) fldt 4(%esp) /* I added the following ugly construct because expl(+-Inf) resulted in NaN. The ugliness results from the bright minds at Intel. For the i686 the code can be written better. -- drepper@cygnus.com. */ fxam /* Is NaN or +-Inf? */ fstsw %ax movb $0x45, %dh andb %ah, %dh cmpb $0x05, %dh je 1f /* Is +-Inf, jump. */ fldl2e fmulp /* x * log2(e) */ fld %st frndint /* int(x * log2(e)) */ fsubr %st,%st(1) /* fract(x * log2(e)) */ fxch f2xm1 /* 2^(fract(x * log2(e))) - 1 */ fld1 faddp /* 2^(fract(x * log2(e))) */ fscale /* e^x */ fstp %st(1) ret 1: testl $0x200, %eax /* Test sign. */ jz 2f /* If positive, jump. */ fstp %st fldz /* Set result to 0. */ 2: ret END (__ieee754_expl)